Results 191 to 200 of about 23,873 (241)

Infrared spectra of pyridinium salts in solution—III. Associations of pyridinium salts with bases

Spectrochimica Acta Part A: Molecular Spectroscopy, 1983
Associations of pyridinium salts X-Py+HA− (A− = SbCl−6, ClO−4, BF−4, I−, Br− and Cl−) with a wide series of aprotic bases and with protic solvents (water and fluoroalcohols) have been studied by infrared spectroscopic methods. Constants of association Ka of the pyridinium salts with the bases at different temperatures have been measured and enthalpy ...
S.E. Odinokov, A.A. Mashkovsky, A.A. Nabiullin   +2 more
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Isolable Pyridinium Trifluoromethoxide Salt for Nucleophilic Trifluoromethoxylation

Organic Letters, 2021
An isolable pyridinium trifluoromethoxide salt is prepared from the reaction of 4-dimethylaminopyridine with the commercially available liquid 2,4-dinitro(trifluoromethoxy)benzene. The salt is an effective trifluoromethoxide source for SN2 reactions to form trifluoromethyl ethers.
Geraldo Duran-Camacho, Devin M. Ferguson, Jeff W. Kampf, Douglas C. Bland, Melanie S. Sanford   +4 more
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Thiazolopyridinium salts. Part II. Approaches to thiazolo[3,4-a]-pyridinium salts and isothiazolo[2,3-a]pyridinium salts

Journal of the Chemical Society C: Organic, 1969
Attempts to synthesise thiazolo[3,4-a]pyridinium salts (3) and isothiazolo[2,3-a]pyridinium salts (2) by dehydration with boiling acetic anhydride of the 5,6,7,8-tetrahydro-8-oxothiazolo[3,4-a]pyridinium salts (11) and (12) and of the 4,5,6,7-tetrahydro-4-oxoisothiazolo[2,3-a]pyridinium salt (6) respectively are reported. The reasons for the failure of
D. G. Jones, Gurnos Jones
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Dimerization of pyridinium salts by cyanide

Journal of the Chemical Society D: Chemical Communications, 1970
1,1′-Dihydro-4,4′-bipyridyls (II) are formed from certain pyridinium or 2-methylpyridinium salts and sodium cyanide.
Lawrence J. Winters, Nelson G. Smith, Martin I. Cohen   +2 more
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Pyridinium salts

Chemistry of Heterocyclic Compounds, 1974
P. P. Zarin', �. S. Lavrinovich, A. K. Aren   +2 more
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Catalytic hydrogenation of pyridinium salts

Chemistry of Heterocyclic Compounds, 1994
Catalytic hydrogenation of polysubstituted pyridinium salts leads to piperidines and their condensed analogs The spatial properties and conformational properties of the saturated azaheterocycles have been determined by13C NMR spectorscopy. It was shown that hydrogenation of the pyridinium salts occurs stereoselectively to form cis isomers in most cases.
P. V. Reshetov, S. A. Rozhnova, A. P. Kriven'ko   +2 more
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Direct C–H Sulfonylimination of Pyridinium Salts

Organic Letters, 2022
A direct pyridinium C-H sulfonylimination has been developed for the synthesis of sulfonyl iminopyridine derivatives with high efficiency. This transformation features the direct and efficient formation of a C═N bond with a high functional group tolerance under metal-free conditions.
Lihua Luo, Juan Tang, Rui Sun, Wenjing Li, Xueli Zheng, Maoling Yuan, Ruixiang Li, Hua Chen, Haiyan Fu   +8 more
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Imidazo [1,2‐a] pyridinium salts

Journal of Heterocyclic Chemistry, 1965
Abstract2‐Alkylamino‐ or arylaminopyridines react directly with α‐bromoketones to afford 1‐alkyl‐ or 1‐arylimidazo[1,2‐a]pyridinium salts with substituents at position 2. Use of chloroacetaldoxime as the quaternizing agent yields (after hydrolysis) the imidazo‐[1,2‐a]pyridinium ion with no substituent at position 2.
C. K. Bradsher, E. F. Litzinger, M. F. Zinn   +2 more
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The reaction of N-nitrosamines with pyridinium salts

Talanta, 1988
N-Nitrosamines react readily with pyridinium salts containing an activated methylene group to give hydrazones. This reaction may serve as the basis for the routine determination of N-nitrosamines.
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Recyclization of polysubstituted pyridinium salts

Tetrahedron, 1995
Abstract 3,5-Diacetyl- and 3,5-dicyano-1,2,6-trimethylpvridinium perchlorates are converted by recyclization into N,5-dimethylanilines and 2-methylaminopyridines, respectively.
Galina P. Shkil, Viesturs Lusis, Dzintra Muceniece, Reva S. Sagitullin   +3 more
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